A couple who want to take their sick baby son to the US for treatment are waiting for a ruling on the latest stage of a legal battle after asking Court of Appeal judges not to take away the "only remaining hope".
Chris Gard and Connie Yates want nine-month-old Charlie Gard, who suffers from a rare genetic condition and has brain damage, to undergo a therapy trial.
Specialists at Great Ormond Street Hospital in London, where Charlie is being cared for, are against any attempt at therapy in the USA and say life-support treatment should stop.
Last month, a High Court judge ruled against a trip to America and in favour of Great Ormond Street doctors.
Mr Justice Francis concluded that life-support treatment should end and said a move to a palliative care regime would be in Charlie's best interests.
Charlie's parents, who are in their 30s and come from Bedfont, west London, hope that appeal judges will overturn Mr Justice Francis's decision.
Lord Justice McFarlane, Lady Justice King and Lord Justice Sales analysed evidence at a Court of Appeal hearing in London on Tuesday.
The say they aim to deliver a ruling on Thursday.
Richard Gordon QC, who led Charlie's parents' legal team, told appeal judges that the case raised "very serious legal issues".
"They wish to exhaust all possible options," Mr Gordon said in a written outline of Charlie's parents' case.
"They don't want to look back and think 'what if?'.
"This court should not stand in the way of their only remaining hope."
Mr Gordon suggested that Charlie might be being unlawfully detained and denied his right to liberty.
He said judges should not interfere with parents' exercise of parental rights and added: "What is really at stake in this case is the State, on a massive scale, intruding in your right to private and family life."
Lawyers, who represented Charlie's parents for free, said Mr Justice Francis had not given enough weight to Charlie's human right to life.
They said there was no risk that the proposed therapy in the US would cause Charlie "significant harm".
Katie Gollop QC, who led Great Ormond Street's legal team, suggested that further treatment would leave Charlie in a ''condition of existence''.
She said therapy proposed in the US was ''experimental'' and would not help Charlie.
''There is significant harm if what the parents want for Charlie comes into effect,'' she said.
''The significant harm is a condition of existence which is offering the child no benefit.''
She added: ''It is inhuman to permit that condition to continue.''
Ms Gollop said nobody knew whether Charlie was in pain.
''Nobody knows because it is so very difficult because of the ravages of Charlie's condition,'' she said.
''He cannot see, he cannot hear, he cannot make a noise, he cannot move.''
Charlie's parents were both at the hearing - Mr Gard snuzzled a toy monkey belonging to Charlie - and left without comment.